Shears with locking means



Sept. 5, 1967 HO CHOW v 3, 3

SHEAHS WITH LOCKING MEANS v Filed May 24, 1965 5 Sheets-Sheet 1 INVENTOR H0 cHoW ATTORNEY Sept; 5, 1 6 HO CHOW 3,339,281

SHEARS WITH LOCKING MEANS Filed May 24, 1965 3 Sheets-Sheet 2 ATTORNEY HO CHOW SHEARS WITH LOCKING MEANS Sept. 5, 1967 Filed May 24, 1965 3 Sheets-Sheet INVENTOR HO CHO W ATTORNEY United States Patent 3,339,281 SHEARS WITH LOCKING MEANS Ho Chow, River Edge, N.J., assignor to International Patent Research Corp., New York, N.Y., a corporation of New York Filed May 24, 1965, Ser. No. 458,317 8 Claims. (Cl. 30-262) The present invention relates to a shears construction provided with means for locking the blades in one or more predetermined relative positions.

Shears, and particularly those used in gardening or horticulture, have cutting blades which are required to perform heavy-duty cutting operations and which are therefore appropriately constructed and actuated. In order to facilitate use of the shears the spring is generally employed to bias the blades to one relative position, usually to the open position. The blades must be protected against damage, and at the same time the users of such devices must be protected against injury from the blades. Consequently it is desirable to incorporate into the shears construction a mechanism which will maintain the blades in a position where they are least susceptible to damage and least likely to cause injury to persons, to wit, the blade-closed position. Hence this locking arrangement must function against the action of the biasing spring which tends to urge the blades to open position.

Sometimes, when the shears are to be used for snipping rather than heavy duty cutting, it is desired to permit the blades to open to only a limited degree, and desirably the lock will accomplish this result as well.

When the lock is moved to full or partial unlocking position, it is important that it reliably remain in that position, so that the shears can be operatively manipulated in as facile a manner as possible. For example, if the lock were to move from unlocking to locking position while the shears are being used, it would obviously interfere with the desired operation of the shears.

It is also desirable that the lock be located on the shears in a position where it can be readily manipulated even when only one hand of the operator is available and while the operator is grasping the shears. (The other hand of the operator may be occupied in holding onto a ladder or grasping the pruned branches, for example.) Such a location of the lock provides the greatest degree of protection both to the shears and to the users thereof, since the shears may be moved in locked position to the very place where it is to be used, unlocked, manipulated in operative fashion, and then, immediately and without difliculty, locked in closed position, even though the user has but One hand available throughout.

It is also desirable that the parts involved be as simple and sturdy as possible, not only from the point of view of minimizing cost, but also from the point of view of maximizing reliability and sturdiness. The fewer the parts in a given construction, the easier it is to manufacture and assemble the structure and the less likely is breakage or damage.

It is the prime object of the present invention to devise a shears construction which will achieve all of the above mentioned objectives and which, in particular, provides a lock means which is movable between locking and unlocking positions, which is reliably retained in those positions, which is so-located and mounted on the shears as to be readily accessible and manipulatable, and which has a high degree of reliability and sturdiness.

The present invention is here disclosed embodied in shears constructions in which, as is conventional, a pair of relatively movable handles are provided, movement of the handles controlling movement of the blades between closed and open positions. The lock means comprises a lock element which is mounted on the shears so as to be readily movable by a finger of the operators hand while that hand is grasping the handles for manipulation thereof. The movable lock member is provided with a positionfixing element which, in at least one of the operative posi tions of the lock member, cooperates with a corresponding position-fixing element on some other portion of the shears. A spring is provided which is active on the lock member so as to urge it in a direction such that the aforementioned position-fixing elements engage with one another, thereby to retain the lock member in the operative position to which it has been moved. The same spring which serves to bias the handles, and hence the blades, to a predetermined relative position (usually a blade-open position) is preferably utilized to exert the aforementioned action on the lock member. One of the handles is provided with a part adapted to engage with a stop surface on the lock member when the latter is in locking operative position, and the handle-biasing spring tends to urge that handle part into engagement with that stop surface.

As here specifically disclosed the position-fixing elements on the lock member and on the other portion of the shears are of the detent type, one of those elements being provided with one or more recesses and the other of those elements being provided with a part adapted to be resiliently urged into those recesses, thereby to retain the lock member in adjusted position. In one specifically illustrated embodiment, the spring itself carries one of those position-fixing elements, the lock member being provided, on a surface facing and engaged by the springcarried element, with the corresponding position-fixing elements. In another specifically illustrated embodiment a surface of one of the handles is provided with the position-fixing elements cooperable with the corresponding elements carried by the lock member, the spring being active to resiliently urge the lock member against that surface.

To the accomplishment of the above, and to such other objects as may hereinafter appear, the present invention relates to the structure of a shears provided with locking means, as defined in the appended claims and as described in this specification, taken together with the accompanying drawings in which:

FIG. 1 is a top plan view of grass shears embodying the present invention;

FIG. 2 is a side elevational view thereof;

FIG. 3 is a fragmentary bottom plan view, on an enlarged scale, of the grass shears of FIGS. 1 and 2;

FIG. 4 is a side elevational view of pruning shears embodying the present invention;

FIG. 5 is a cross sectional view on an enlarged scale of the grass shears embodiment, taken along the line 55 of FIG. 1, and showing the parts in blade-closed-andlocked position;

FIG. 6 is a view similar to FIG. 5, but showing the parts in a position in which the blades are locked in a partially open position;

FIG. 7 is a cross sectional view of the pruning shears embodiment showing the blades locked in closed positron;

FIG. 8 is a cross sectional view similar to FIG. 7, but taken along the line inside the outer wall of the lower handle visible in FIG. 7 and showing the blades locked in partially open position; and

FIG. 9 is a view similar to FIG. 8, but showing the blades unlocked, in fully open position.

Turning first to the grass shears embodiment of FIGS. 1-3, 5 and 6, the shears comprise a support housing generally designated 2 which is formed integrally with the upper fixed handle, generally designated 4. The handle 4 and support housing 2 may be considered structurally as a single element, with no true line of demarcation between them. The handle 4 is channel-shaped in cross-section, comprising a top wall 6 and depending side walls 8. The top wall 6 is provided, adjacent the support housing 2, with an elongated aperture 10. A blade generally designated 12, having a cutting edge 14, is fixedly secured to the lower end of the support housing 2 in any appropriate manner, and extends out therefrom in a direction opposite to the upper handle 4.

The lower handle generally designated 16 is also channel-shaped in cross section, and comprises a bottom wall 18 and upstanding side walls 20. Its left-hand end is received inside the support housing 2 and is there pivotally mounted, as by means of a pin 22 which extends between the side walls 24 of the support housing 2 and which passes through apertures 26 in the enlarged side wall portions 20a of the lower handle 16. The lower handle 16 is therefore movable in a pivotal fashion about the pin 22 toward and away from the upper handle 4, the two handles being in vertical alignment.

A movable blade generally designated 28 and provided with cutting edge 30 is positioned on top of the fixed blade 12, and is mounted for pivotal movement in the following fashion: The lower fixed blade 12 is provided with an aperture 32 through which a stud 34 extends up- 'wardly, the tip of the stud being threadedly received within an aperture 36 in a downwardly extending portion 38 of the support housing 2. The stud 34 passes through an aperture 40 in the upper and movable blade 28. The apertures 40 and 32 are large enough to receive the downwardly extending reduced-sized tip 42 of the downwardly extending housing portion 38, and a tapered bushing 44 is preferably received around that portion 42 and passes through the aperture 40 in the blade 28. A compression spring 46 is received around the portion 38 and engages and presses the movable blade 38 downwardly toward the fixed blade 12. The tail portion of the movable blade 28, that is to say, that portion which extends to the right of the pin 34 as viewed in the drawings, in provided with a downwardly extending projection 47 which rides on the tail of the lower blade 12, and is further provided with an arcuate slot 48 in which a pin 50 depending from the bottom wall portion 18a of the lower and movable handle 16 is received. Thus as the handle 16 is moved up and down relative to the fixed handle 4, the blade 28 will be caused to pivot about the pin 34 from a closed position in which the cutting edge portions 14 and 30 of the blades 12 and 28 overlap (see the phantom line showing in FIGS. 1 and 3) and an open position in which the blades 12 and 28 are spread apart (see the solid line showing in FIGS. 1 and 3).

The lock means, generally designated 52, comprises a lock member 54 having a first part 56 which extends above the upper surface of the top wall 6 of the handle 4, a second part 58 which extends through and is movable along the elongated aperture 10, and a third part 60 which is received in the space between the handles 4 and 16. An operating button 62 may be secured to the lock member part 56 to facilitate manipulation thereof, the button 62 sliding over the upper surface of the handle top wall 6 and being adapted to register, in the operative positions of the lock means 52, with suitable indicia 64, 66 and 68 provided on that upper surface.

The third part 60 of the lock member 54 includes a depending element 70 having a pair of upwardly facing and upwardly and laterally displaced stop surfaces 72 and 74. The lower handle 16 has a pin 76 extending between its side Walls 20 and adapted to engage with the stop surfaces 72 and 74. The third part 60 of the lock member 54 also comprises a member 78 which extends to the rightas viewed in the drawings beneath the top wall 6 of the upper handle 4 and which is provided with an upwardly projecting part 80 adapted to slide along the under surface of the wall 6. For bearing and balancing purposes the third part 60 of the lock member 54 is provided with portion 82 extending to the left as viewed in the drawings and sliding along the undersurface of the wall 6 to the left hand side of the aperture 10. The end surface of the wall 6, where the portion slides thereover, is provided with a plurality of depressions 84, 86 and 88 into which the part 80 is selectively receivable.

The biasing spring generally designated 90 has a coiled portion 92 extending freely around the pin 22, an arm 94 extending down to and engaging the upper surface of the bottom wall 18 of the movable handle 16, and an arm 96 extending to and engaging the lower surface of the portion 78 of the lock member 54. The resiliency of the spring 90 is such that the arms 94 and 96 tend to spread apart, thereby biasing the lower handle 16 to its lower position, corresponding to a blade-open position, and also biasing the portion 78 of the lock member 54 upwardly so as to urge the portion 80 against the lower surface of the handle wall 6 and into a recess 84, 86 or 88.

When the handle 16 is moved upwardly toward the handle 4 so as to fully close the blades, the pin 76 carried thereby is at an elevation corresponding to (slightly higher than) the stop surface 74 on the lock member 54. If that lock member is then moved to the right as viewed in the drawings, and as shown in FIG. 5 and the phantom lines in FIG. 2, the pin 76 will be engaged with the stop surface 74, thus locking the blades closed. At the same time the lock member portion 80 will be urged into recess 84 by the spring arm 96, and the button 62 will cover the indicia 66 and 68, but will leave indicia 64 exposed, that indicia typically reading Lock.

If now it is desired to unlock the blades the operator, while grasping the handles, may with his thumb quite readily push the button 62 to the left as viewed in the drawings, possibly to the intermediate position shown in FIG. 6 and the broken lines in FIG. 2. A moderate amount of pressure will be required to accomplish this movement because the spring arm 96 produces detent action between the portion 80 and the recess 84. When the button 62, and with it the lock member 54, has been moved to the intermediate position shown in FIG. 6, the spring arm 96 will urge the portion 80 into the recess 86, thus producing a detent action retaining the lock member 54 in that intermediate position. When the lock member 54 is in said intermediate position, the pin 76 carried by the handle 16 will move downwardly into engagement with the stop surface 72, thus permitting the handles to spread apart a predetermined amount, thereby causing the blades to spread apart a predetermined amount, as indicated by the broken lines in FIG. 1. In this position the button 62 will expose the indicia 66, which may typically read Half (since the blades are locked half open), and the lower handle 16 can be moved toward and away from the upper handle 4, against the bias of the spring 90, to cause a limited degree of shearing action to take place.

If it is desired to open the shears completely the button 62 is pushed all the way to the left, to the position shown in FIG. 1 and in solid lines in FIG. 2, the button then exposing indicia 68, which may typically read Open. This will move the lock member 54 all the way to the left, as indicated by the phantom lines in FIG. 5, and completely out of the way of the pin 76 carried by the handle 16, thus permitting the blades to move to their fully open position as shown in solid lines in FIGS. 1-3. The lock member 54 will be detent-held in this Open position by virtue of the spring-pressed detent-type interengagement between the portion 80 of the lock member 54 and the recess 88 in the undersurface of the top handle wal 6.

Thus, the part 80 constitutes a position-fixing element carried by the lock means 54 and the recesses 84, 86 and 88 constitute cooperating position-fixing elements on another portion of the shears, to wit, on the handle 4 which constitutes an integral part of the support housing 2.

The pruning shears embodiment of FIGS. 4 and 7-9 is diiferently constructed from the grass shears embodiment previously described, in part because of the different type of cutting operation which it must perform, but its locking mechanism and basic mode of construction and operation are in many respects similar to those of the grass shears embodiment. Accordingly,'where appropriate, parts in the pruning shears embodiment comparable to correspond-ing parts in the grass shears embodiment will be given similar reference numerals, differentiated, however, by being primed.

Thus the pruning shears comprise a support housing generally designated 2' which is fixed to and constitutes an integral extension of the fixed handle 4'. The blade 12' with cutting edge 14 is articulately mounted on the support housing 2', as by being pivotable about pin 98 which carried by the forwardly extending portion 100 of the support housing 2'. The handle 16' is pivotally mounted on pin 22' carried by the support housing 2', and blade 28-, provided with cutting edge 30', i fixed to the handle 16'. as by pin 102 for integral movement therewith. The blade 12' is provided with the arcuate slot 48 through which pin 50', carried by the lower handle 16', passes. (The handles 4 and 16' are so designated because they are the upper and lower handles respectively, and the blades 12' and 28' are so designated because they are operatively connected to the handles 4 and 16' respectively, thus corresponding in those respects to the similarly numbered parts of the grass shears embodiment. However, the analogy is not exact in all respects. Thus, for example, it will be noted that in the pruning shears embodiment blade 28' is fixed to handle 16', and blade 12' is movable relative to handle 4'. Consequently, the numbering employed is in many respects arbitrary.)

The upper wall 6' of the handle 4' is provided with elongated aperture and the lock means 52' comprises lock member 54 having parts 56', 58' and 60', all similar in structure and function to the correspondingly numbered parts in the previously described embodiment. The portion 78' of the lock member 54 is, however, provided with a smooth upper surface slidable along the lower surface of the handle wall 6, and is further provided, at its lower surface, with a plurality of recesses 84', 86 and 88' which correspond functionally with the recesses 84, 86 and 88 of the previously described embodiment. The downwardly depending portion 70' of the lock member 54 is provided with stop surfaces 72' and 74' which are adapted to be engaged by a rearwardly extending portion 76' of the blade 28'; The spring 90' has a coiled portion 92' which extends around the pin 22', has a lower arm 94' which engages with finger 104 bent out through the enlarged side wall portion 20a of the handle and an upper arm 96' provided with a laterally extending finger portion 106 which engages the underside of the lock member portion 78' and is adapted to be selectively received in one or another of the recesses 84', 86 and 88'. Thus the recesses 84', 86' and 88' constitute a position-fixing element on the lock means 52, while the finger 106 carried by the spring arm 96 constitutes the position-fixing element carried by a portion of the shears other than the lock means 52 and adapted to interengage in resilient detent fashion with the recesses 84, 86 and 88'.

The functioning and mode of operation of the pruning shears embodiment insofar as manipulation and locking are concerned, is essentially the same as that of the grass shears embodiment. The spring 90' acts on the lower handle 16' through the finger 104 and on the upper handle 4 through the portion 78' of the lock member 54 to urge those handles apart, thereby urging the blades 12' and 28' to their open position shown in FIG. 9. When the handles 4' and 16' are grasped and pulled together against the action of the spring 90, the blades 12' and 28 are moved together to closed position, thereby cutting anything located therebetween. When the handles 4 and 16 are close to one another the operator, by using his thumb,

can push the button 62' of the locking means 52' forwardly to the position shown in FIG. 7, the stop surface 72 on the locking member 54 thus being interposed beneath the rearward extension 76' of the blade 28 fixed to the lower handle 16', thus locking the handles and blades in closed position. The action of the finger 106 carried by the spring arm 96', which is resiliently urged into recess 84, serves to hold the locking means 52 in its locking position. If it is desired to permit the blades to open part way, the button 62 is pulled back part way until the finger 106 carried by the spring arm 96' snaps into recess 86', at which time the stop surface 74' engages the rearward blade extension 76' (see FIG. 8). When it is desired that the blades open to their fullest extent, the button 62' is pulled back until the spring-carried finger 106 snaps into recess 88, at which time the lock member 54 is located completely to one side of the rearwardly projecting blade extension 76' (see FIG. 9). At all times the spring serves to bias the blades and handles to their open position, serves to urge the extension 76 against a stop surface 72 or 74 when that extension and the corresponding surface are in interengaging position, and serves to provide the position-fixing detent action which prevents the locking means 52 from moving from one of its operative positions to another unless an appreciable amount of force is manually exerted thereon.

Thus it will be seen that the structures in question, particularly with regard to their locking action and the manual adjustment thereof, are characterized by a high degree of sturdiness and reliability, are easily manufactured and assembled from parts which need not be made to any high degree of dimensional precision, and are particularly well adapted to one-hand manipulation both with regard to causing the blades to exert a cutting action and with regard to controllably bringing about a locking action on the handles and blades.

While the structures here specifically disclosed provide for two stages of locking and for an unlocked stage, it will be understood that this is by way of exemplification only. A single locking stage, or more than two locking stages, could be provided if desired. The position-fixing detent action on the locking means is accomplished in specifically different fashions in the two illustrated embodiments, but it will be understood that this also is by way of exemplification only, and that the structures could be interchanged. Other structures could be employed to accomplish the position-fixing functions while at the same time maintaining the basic relationship of parts inherent in this disclosure. Many other variations may be made in the specific details of the illustrated disclosures, all without departing from the spirit of the invention as defined in the following claims.

I claim:

1. In shears comprising a support, a pair of blades mounted thereon for relative movement toward and away from one another, a pair of handles mounted on said support for relative movement, and operative driving connections between said handles and said blades; lock means mounted on a surface of said shears so as to be slidable thereover between a plurality of operative positions and operatively engageable with one of said handles in at least one of said operative positions so as to retain said handles and said blades in a predetermined relative position, cooperating detent means on said lock means and on another portion of said shears for retainmeans into operative engagement with said detent means on said lock means.

3. The shears of claim 1, in which said lock means is interposed between said spring means and one of said handles and is operatively connected to said one of said handles, said spring means engaging said lock means on the side thereof away from said one of said handles and being effective to bias it toward said one of said handles, thereby exerting force on said one of said handles to bias it to said given position relative to the other handle.

4. The shears of claim 1, in which said detent means on said other portion of said shears is located on the side of said lock means away from said spring means, said spring means engaging said lock means on the side thereof away from said detent means to urge said lock means toward said detent means.

5. Shears comprising a support, a first handle fixed to said support and a second handle mounted on said support so as to be pivotable about an axis relative to said first handle, a first blade mounted on said support, a second blade mounted on said support for movement toward and away from said first blade, an operative driving connection between said second handle and said second blade, lock means movably mounted on said first handle and movable between a plurality of operative positions, said lock means having a part movable over a surface of said first handle, position-fixing elements on said lock means part and on another portion of said shears adapted to interengage in at least one operative position of said lock means, and spring means mounted on said shears, surrounding said axis, operatively connected to said handles and effective to bias them to a given relative position, and operatively connected to said lock means and effective to bias said lock means part toward said surface of said first handle and to bias said position-fixing elements into interengagement.

6. The shears of claim 5, in which said position-fixing element on said other portion of said shears comprises a part carried by said spring means and urged by said spring means into operative engagement with said position-fixing element on said lock means.

7. The shears of claim 5, in which said position-fixing element on said other portion of said shears is located on said inner surface of said first handle, said spring means engaging said lock means part on the side thereof away from said inner surface of said first handle.

8. The shears of claim 5, in which said inner handle surface is opposite said second handle and said positionfixing element on said other portion of said shears is located thereon, said lock means part is interposed between said handles, and said spring means comprises a single arm means which engages said lock means and is effective to bias said lock means part against said handle surface, thereby simultaneously biasing said handles to a given relative position and biasing said position-fixing elements into interengagement.

References Cited UNITED STATES PATENTS 154,637 9/1874 Breeden 30262 2,715,270 8/1955 Exhandlcr 30-262 2,731,721 1/1956 Traurig 30-249 X 2,821,018 1/1958 Schieso 30271 X WILLIAM FELDMAN, Primary Examiner.

I. C. PETERS, Assistant Examiner. 

1. IN SHEARS COMPRISING A SUPPORT, A PAIR OF BLADES MOUNTED THEREON FOR RELATIVE MOVEMENT TOWARD AND AWAY FROM ONE ANOTHER, A PAIR OF HANDLES MOUNTED ON SAID SUPPORT FOR RELATIVE MOVEMENT, AND OPERATIVE DRIVING CONNECTIONS BETWEEN SAID HANDLES AND SAID BLADES; LOCK MEANS MOUNTED ON A SURFACE OF SAID SHEARS SO AS TO BE SLIDABLE THEREOVER BETWEEN A PLURALITY OF OPERATIVE POSITIONS AND OPERATIVELY ENGAGEABLE WITH ONE OF SAID HANDLES IN AT LEAST ONE OF SAID OPERATIVE POSITIONS SO AS TO RETAIN SAID HANDLES AND SAID BLADES IN A PREDETERMINED RELATIVE POSITION, COOPERATING DETENT MEANS ON SAID LOCK 